This invention relates generally to release devices and more particularly, to a direct-acting pin release device in which the pull pin separates from the release pin at a predetermined throw.
In many deep ocean applications in which free-surfacing vehicles are released to the surface from a deep submergence vehicle (DSV), the final release requires that a large release pin be pulled by the DSV's manipulator arm. For example, the design of a free-surfacing cable reel required a pin pull to first release the reel from the DSV, and a second pin pull to start the reel on its journey to the surface. In both cases, however, the pin throw required to release the reel was less than the throw required to disengage the release pin from the frame which is attached to the reel and also supports the release pins. As a consequence, a dangerous situation is possible in which the reel may be released (i.e., a weight may be dropped or a trigger released even though the DSV manipulator is still connected to it because the release pin is still in the frame. If the DSV manipulator is holding onto the release pin, it is in contact with the release reel, and therefore in a precarious position.
In order to eliminate the type of problem, release devices have been designed that trip the final release mechanism indirectly. The manipulator pulls a pin with a short throw which, in turn, triggers another trip and activates the main release pin. The main release pin is almost always spring activated. Consequently, the spring which operates the main release must be strong enough to release the tension of whatever the pin is locking. The pull of the manipulator on the pin has no direct effect on the final release which depends directly on the spring tension.